The role of dynamin in the assembly and function of podosomes and invadopodia.

Cells make contact with the extracellular matrix (ECM) through extensions of the plasma membrane; these range from irregular dynamic structures, e.g. lamellipodia, ruffles and pseudopodia, to more localized and highly defined protrusions, e.g. podosomes and invadopodia. Both might be instruments through which cells sample the immediate extracellular environment and maintain polarized activities such as chemotaxis and focal degradation of the matrix. Podosomes are expressed in cells of the monocytic lineage, and most studies point to a role for podosomes in adhesion/motility. Invadopodia are prominent in certain aggressive cancer cells (or transformed cells) and appear to be directly responsible for focal ECM degradation. Recent studies have revived interest in these structures in terms of the actin regulation machinery. Within this framework, the atypical GTP-binding protein dynamin, a central modulator of protrusive events, has been associated to podosome and invadopodia structure and function. Here, we specifically discuss the role played by dynamin in controlling the activities and function of these structures.